One mechanism by which smoke and fire may spread from one compartment of a building to another is through passages or openings, often referred to as through-penetrations, in floors, walls, ceilings, or the like. Such openings are provided to allow for the passage of cables, wires, pipes or the like within the building.
Current methods used to prevent the spread of fire and passage of smoke through such openings use intumescent sheets that are cut to follow the contour of the penetrating cables. A bead of moldable intumescent putty is provided along the perimeter of the sheets.
While such techniques are generally satisfactory for resisting the spread of fire and preventing the passage of smoke from one compartment to another, installation is labor intensive, time consuming, and expensive. In addition, when intumescent sheets, bricks, or pillows are used, they must be mechanically attached to or physically compressed in the opening, or both, to pass the hose stream portion of the fire test defined in ASTM E814-02. Firestops fabricated in this manner also do not lend themselves to repeated re-entry for inspection, do not readily allow additional cables or wires to be run through the opening, and do not allow cables to be readily removed from the opening. To remove cables from a typical through-penetration, for example, requires the existing intumescent material to be removed, discarded, and replaced with completely new intumescent material. This procedure is time consuming, expensive, and wasteful. Because through-penetrations may be opened and closed numerous times during the life of a building to add or remove items from the opening, the costs associated with such systems can be significant.
Furthermore, such systems require cover plates to meet fire and architectural demands. Cover plates are typically made of 0.25 inch (6.4 millimeters) steel which makes them difficult to fabricate. Typically, such cover plates must be removed from the area of the through-penetration or even from the building to make necessary modifications.
Even though the present invention does not require a cover plate, some form of cover may be desirable in floor applications for safety reasons. However, because the present invention does not require a cover plate for floor openings, end users may select materials of their choice that are easier and less costly to modify. Alternatively, the apparatus according to the present invention may be combined with a cover plate capable of being extended and retracted to adapt to the items passing through the opening.
Techniques for fire stopping through-penetrations are also known in the prior art. U.S. Pat. No. 4,496,790 (Spencer), for example, discloses a self-anchoring poke-thru wiring device for the extension of communication and/or electrical wiring through a passage in a floor designed to prevent the spread of fire from one side of the floor to the other.
U.S. Pat. No. 4,493,173 (Kohaut) discloses a cable passage closure and sealing device for positioning in an opening in a structure such as a floor or wall that is used for passing or connecting a cable or cables and cable conduits there through. The device automatically expands and seals itself and the cables and the cable conduits in the structural opening upon exposure to excess heat or fire.
These prior devices and techniques, however, suffer from certain drawbacks or shortcomings. Accordingly, there exists a need in the industry for a method and apparatus for firestopping a through-penetration that allows items passing through the opening to be readily added or removed. An adjustable firestop device that never needs to be removed or modified and is easy to open and close can provide considerable long-term cost saving to firestop users over currently available systems and techniques.